8010 



Insects. 



precisely that shape into which a series of cylinders, composed of any 

 plastic material, would be forced on being subjected to uniform ex- 

 ternal pressure. In the basaltic columns of the Giant's Causeway, 

 and of other places, we have the reverse operation of contraction ; and 

 notwithstanding the many disturbing influences during the cooling 

 down of the once incandescent matter, the perpendicular fissures have 

 separated the basaltic mass into columns, whose sections are mostly 

 hexagonal. 



It is a striking and an important fact that no instance has ever 

 been brought forward of a bee of any species making a detached 

 or isolated polygonal cell. Whenever wild bees make single cells 

 they are invariably of the cylindrical shape. Hive-bees produce their 

 ordinary comb-cells by the united efforts of many individuals. Owing 

 to this circumstance, and also to their never building up cells at the 

 margins of the combs unflanked by the foundations of other cells, 

 they afford us, when so employed, no opportunity for observing the 

 fundamental scheme upon which they build. Every cell during its 

 progress is impinged upon by six other cells, and, as all progress at 

 the same time, the united attempts of the workers to avoid interspaces, 

 and to expend no more wax than is necessary to the making of firm 

 walls, produce inevitably the hexagonal structure. The royal cells, 

 or cells containing larvae destined to become queens, are constructed 

 upon the ordinary comb, and at right angles to the other cells. These 

 cells are unconnected with each other, and it is an important fact that 

 they are always cylindrical in shape : but the fact upon which I 

 mainly found my disbelief in the hexagonal type is, that under ex- 

 ceptional circumstances, and where the hexagonal is not the shape 

 that results from a compressed cylinder, other shapes are assumed. 

 In the specimens which I now lay before you, examples are to be 

 seen of pentagonal and also of heptagonal cells. This departure from 

 the ordinary type has undoubtedly arisen either from the combs 

 having been founded upon irregular base-lines, or, as in some cases, 

 from the interspersing of large drone-cells among the series of the 

 smaller cells which are destined for workers, and the consequent de- 

 rangement of what may be called the ground-plan. These examples 

 prove to my mind that bees, so far from aiming at producing a cer- 

 tain number of angles, attempt merely to form cylindrical cells, com- 

 modious as to size, and with as little expenditure of wax as possible ; 

 and whenever any particular cell impinges upon five, six or seven 

 other cells, the thickness of the intervening wax being kept down to 

 a minimum, the result is a cell with just so many corresponding sides, 



